Temperature profile measurement of graphite material using a CO₂laser

Abstract

Emissive probes have been used for the direct measurement of plasma potential in many plasma devices and different approaches have been introduced to measure plasma potential using emissive probes. But the biggest disadvantage of the emissive probe is its short lifespan due to its self-arrangement and different plasma environment. For example, filament emissive probes cannot be used in high-temperature plasma devices. A few initiatives have begun to measure the plasma potential by using a laser-heated emissive probe. In these cases, mostly graphite and LaB6 are being used as a probe tip to emit electrons by heating them with a laser light. However, very few studies aiming to understand the mechanism of the heating process of the graphite material have been performed. The heating dynamics of the graphite material heated by a CW CO2 laser with a maximum power of 30 W have been investigated in this study. The in situ temperature of the probe tip has been measured by using an infrared camera. Complete theoretical and simulation models have been developed to understand the experimentally measured data. Further, the experimental results are compared with ANSYS simulations.

Flame temperature trends in reacting vanadium and tungsten ethoxide fluid sprays during CO2-laser pyrolysis

“…Also, since the flame is not in vacuum, but rather is surrounded by C 2 H 2 and Ar gases, the radiation loss rate is modified [19] …”

“…The integration limits ω 1 and ω 2 are the FTIR detector ranges of 909 cm −1 (a wavelength of 12 µm) and 1250 cm −1 (a wavelength of 7.5 µm), respectively. The rate of energy loss through convection is given [19] by the very well-known relation (∂C/∂t) convection = κ conv A(T − T s ) where κ conv is the coefficient of convection. Since there is no contact with the wall of the chamber, the energy loss to conduction, κ cond A(∂T /∂r), is zero.…”

Time-Resolved Growth of 2D WSe2 Monolayer Crystals

“…Turning off the laser and the furnace at the same time (t = 3 s) terminated the growth process. boat 35 containing the precursor powders achieved a high enough temperature in a short time to evaporate the stoichiometric powders (Figure 1). This technique addressed the key challenge involved in growing 2D materials from their bulk counterparts due to the significant difference between the vaporization temperatures of stoichiometric powders and their growth temperatures.…”

“…A laser vaporization process allowed localized vapor flux generation by direct vaporization of stoichiometric powders, while eliminating the need for precursor mixing and complex chemistry for the growth process. The localized laser heating of a graphite boat containing the precursor powders achieved a high enough temperature in a short time to evaporate the stoichiometric powders (Figure ). This technique addressed the key challenge involved in growing 2D materials from their bulk counterparts due to the significant difference between the vaporization temperatures of stoichiometric powders and their growth temperatures.…”

Emerging laser-assisted vacuum processes for ultra-precision, high-yield manufacturing

“…3b). 63 Due to the high infrared absorbance of the graphite, the graphite boat heats up rapidly to each evaporation temperature of the four representative primary TMDCs 2D materials that are about 300 °C higher than the Si/SiO 2 substrate for growth (Fig. 3c).…”